Quadratic inequalities: graph and solve

Answer Key - Grade 11 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Luz solves x² − 2x − 8 < 0 by finding the zero rows. What is the answer, written like 2 < x < 9?

   -2 < x < 4
2. 2.

   Noah solves x² + 6x + 5 < 0 by finding the zero rows. What is the answer, written like 2 < x < 9?

   -5 < x < -1
3. 3.

   Pia solves x² − 8x + 7 ≤ 0 by finding the zero rows. What is the answer, written like 2 < x < 9?

   1 ≤ x ≤ 7
4. 4.

   Ren solves x² + x − 12 > 0 by finding the zero rows. What is the answer, written like x < 1 or x > 6?

   x < -4 or x > 3
5. 5.

   Zee solves x² + 3x − 10 ≥ 0 by finding the zero rows. What is the answer, written like x < 1 or x > 6?

   x ≤ -5 or x ≥ 2
6. 6.

   Esme solves x² − 11x + 24 > 0 by finding the zero rows. What is the answer, written like x < 1 or x > 6?

   x < 3 or x > 8
7. 7.

   Jun solves x² + 10x + 21 ≥ 0 by finding the zero rows. What is the answer, written like x < 1 or x > 6?

   x ≤ -7 or x ≥ -3
8. 8.

   Luz solves -x² + 4x + 12 > 0, where the parabola opens down. What is the answer, written like 2 < x < 9?

   -2 < x < 6
9. 9.

   Milo solves -x² + 4x + 5 ≥ 0, where the parabola opens down. What is the answer, written like 2 < x < 9?

   -1 ≤ x ≤ 5
10. 10.

    Noah solves -x² − 4x + 12 < 0, where the parabola opens down. What is the answer, written like x < 1 or x > 6?

    x < -6 or x > 2